Administration of the MapR-DB is done primarily via the command line (maprcli) or with the MapR Control System (MCS). Regardless of whether the MapR-DB table is used for binary files or JSON documents, the same types of commands are used with slightly different parameter options. MapR-DB administration is associated with tables, columns and column families, and table regions.

The MapR Data Access Gateway is a service that acts as a proxy and gateway for translating requests between lightweight client applications and the MapR cluster. This section describes considerations when upgrading the service, how to modify configuration settings, and how to administer and manage the service.

disksetup

The disksetup command formats specified disks for
use by MapR storage and adds those disks to the disktab file.

You do not need to set up RAID (Redundant Array of Independent Disks) on disks used by
MapR-FS. MapR uses disksetup to set up storage pools.
In most cases, you should let MapR calculate storage pools using the default stripe width of two or three disks. If you anticipate a high volume
of random-access I/O, you can use the -W option to specify larger
storage pools of up to 8 disks each.

Syntax

Options

Option

Description

-F

Forces formatting of all specified disks. Disks that are already
formatted for MapR are not reformatted by disksetup
unless you specify this option. The -F option fails
when a filesystem has an entry in the disktab file, is mounted, or is
in use. Call maprcli disk
remove to remove a disk entry from the
disktab file.

-G

Generates disktab contents from input disk list,
but does not format disks. This option is useful if disk names
change after a reboot, or if the disktab file is
damaged.

-M

Uses the maximum available number of disks per storage pool.

-W

Specifies the number of disks per storage pool.

Examples

Setting up disks specified in the file
/tmp/disks.txt:

/opt/mapr/server/disksetup -F /tmp/disks.txt

Reformatting
all disks

To reformat all disks, remove the disktab file and
issue the disksetup -F command to format the disk:

The disksetup script is used to format disks for use by the MapR cluster. Create a text file
/tmp/disks.txt listing the disks and partitions for use by MapR on
the node. Each line lists either a single disk or all applicable partitions on a single
disk. When listing multiple partitions on a line, separate by spaces. For example:

/dev/sdb
/dev/sdc1 /dev/sdc2 /dev/sdc4
/dev/sdd

Later, when you run disksetup to format the disks, specify the
disks.txt file. For example:

/opt/mapr/server/disksetup -F /tmp/disks.txt

Note:

The script disksetup removes all data from the specified disks. Make
sure you specify the disks correctly, and that any data you wish to keep has been
backed up elsewhere.

If you are re-using a node that was used previously in another cluster, be sure to
format the disks to remove any traces of data from the old cluster.

When setting up a small
cluster for evaluation purposes, if a particular node does not have physical disks or
partitions available to dedicate to the cluster, you can use a flat file on an existing
disk partition as the node's storage. Create at least a 16GB file, and include a path to
the file in the disk list file for the disksetup script.